Intermediate frame, electrochemical systems, and methods

ABSTRACT

Provided herein are intermediate frame systems and methods, comprising one or more arrays of channels on upper and/or lower edges of the intermediate frame wherein the channels are configured to provide a spatially uniform flow of electrolyte through the plane of the intermediate frame.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims benefit to U.S. Provisional Patent ApplicationNo. 62/327,635, filed Apr. 26, 2016, which is incorporated herein byreference in its entirety in the present disclosure.

BACKGROUND

Three chamber electrolytic cells may contain an anode chamber, a cathodechamber, and an intermediate chamber. These electrolytic cells maycontain ion exchange membranes such as anion and cation exchangemembranes interposed between the anode and the cathode such that theanion exchange membrane is interposed between the anode and theintermediate chamber and the cation exchange membrane is interposedbetween the cathode and the intermediate chamber. The intermediatechamber in the electrolytic cells may be subject to several constraintssuch as, the separation of the membranes by the intermediate chamber mayneed to be minimized; the brine flow through the intermediate chambermay need to be uniform; and the membranes may not contact each other.Therefore, there is a need for the intermediate chamber that results inadequate distance between the membranes as well as provides uniform flowof the brine in the cell.

SUMMARY

In one aspect, there is provided an intermediate frame in anelectrochemical cell, comprising one or more arrays of channels on upperand/or lower edges of the intermediate frame wherein the channels areconfigured to provide a spatially uniform flow of electrolyte throughthe plane of the intermediate frame.

In some embodiments of the foregoing aspect, the intermediate framecomprises between about 1-20 or between about 3-10 channels in each ofthe one or more arrays. In some embodiments of the foregoing aspect andembodiments, the intermediate frame comprises between about 1-35 orbetween about 3-35 of the arrays of channels on each of the upper and/orlower edges of the intermediate frame. In some embodiments of theforegoing aspect and embodiments, each of the channels has a depth ofbetween about 0.25-10 mm or between about 0.25-4 mm. In some embodimentsof the foregoing aspect and embodiments, each of the channels is in ashape of a circle, semi-circle, rectangular, triangular, trapezoidal, orthe like.

In some embodiments of the foregoing aspect and embodiments, theintermediate frame further comprises distribution pockets located at anend of each of the one or more arrays of channels, configured todistribute the electrolyte to the one or more arrays of channels. Insome embodiments of the foregoing aspect and embodiments, thedistribution pockets are between about 6-70 mm wide.

In some embodiments of the foregoing aspect and embodiments, theintermediate frame further comprises a manifold located at an end of theupper and/or the lower edges of the intermediate frame, operablyconnected to the distribution pockets and configured to provide theelectrolyte to the distribution pockets.

In some embodiments of the foregoing aspect and embodiments, theintermediate frame further comprises a cap over each of the one or morearrays of channels and the corresponding distribution pocket configuredto prevent the electrolyte from leaking.

In some embodiments of the foregoing aspect and embodiments, theintermediate frame further comprises a shim under the cap and over eachof the one or more arrays of channels and the corresponding distributionpocket configured to prevent the cap from flowing into the channels. Insome embodiments of the foregoing aspect and embodiments, the shim ismade of material selected from the group consisting of titanium,titanium alloy, stainless steel alloy, nickel, nickel alloy, aluminum,aluminum alloy, copper, copper alloy, hastelloy alloy, inconel alloy,glass-filled chlorinated polyvinyl chloride (CPVC), Rulon®,polyetheretherketone (PEEK), glass-filled polytetrafluoroethylene(PTFE), polypropylene (PP), glass-filled polypropylene (PP), fiberglassreinforced plastic (FRP), polycarbonate, and combinations thereof. Insome embodiments of the foregoing aspect and embodiments, the shim has athickness of between about 0.1-1 mm.

In some embodiments of the foregoing aspect and embodiments, theintermediate frame further comprises a reinforcement bar over a portionof the cap configured to prevent the cap from bulging out.

In some embodiments of the foregoing aspect and embodiments, thethickness of the intermediate frame is between about 0.75-30 mm orbetween about 1-6 mm.

In some embodiments of the foregoing aspect and embodiments, theintermediate frame further comprises a spacer in an open area in middleof the intermediate frame. In some embodiments of the foregoing aspectand embodiments, the intermediate frame further comprises means to holdthe spacer in place.

In some embodiments of the foregoing aspect and embodiments, theintermediate frame is configured to withstand temperature between about70-150° C. In some embodiments of the foregoing aspect and embodiments,wherein the intermediate frame is configured to withstand pressurebetween 2-10 psi.

In some embodiments of the foregoing aspect and embodiments, theintermediate frame is made of titanium or polymeric material.

In one aspect, there is provided an intermediate frame in anelectrochemical cell, comprising one or more arrays of channels on upperand/or lower edges of the intermediate frame wherein the channels areconfigured to provide a spatially uniform flow of electrolyte throughthe plane of the intermediate frame wherein the intermediate framecomprises between about 1-20 or 3-7 channels in each of the arrays,wherein the intermediate frame comprises between about 1-35 or 5-25arrays of channels on each of the upper and/or lower edges of theintermediate frame, and optionally wherein the depth of each of thechannel is between about 0.25-10 mm or 0.25-4 mm.

In one aspect, there is provided an electrochemical cell, comprising theintermediate frame of any one of the preceding aspects and embodiments.

In one aspect, there is provided a method of using an intermediate framein an electrochemical cell, comprising:

applying voltage to an anode and a cathode in an electrochemical cell;

contacting the anode with an anode electrolyte in an anode chamber;

contacting the cathode with a cathode electrolyte in a cathode chamber;and

contacting an electrolyte with an intermediate frame wherein theintermediate frame comprises one or more arrays of channels on upperand/or lower edges of the intermediate frame wherein the channels areconfigured to provide a spatially uniform flow of electrolyte throughthe plane of the intermediate frame.

In some embodiments of the foregoing aspect and embodiments, theintermediate frame withstands temperature between about 70-150° C.and/or the intermediate frame withstands pressure between 2-10 psi.

In some embodiments of the foregoing aspect and embodiments, thechannels provide a spatially uniform flow of the electrolyte through thewidth of the electrochemical cell.

In some embodiments of the foregoing aspect and embodiments, the methodfurther comprises contacting an anion exchange membrane between theintermediate frame and the anode and contacting a cation exchangemembrane between the intermediate frame and the cathode.

In some embodiments of the foregoing aspect and embodiments, theintermediate frame provides advantages selected from the groupconsisting of minimal membrane separation; uniform current density; nobending of the membrane; low dynamic pressure in the cell; minimalresistance to the electrolyte and gas; and combinations thereof.

In some embodiments of the foregoing aspect and embodiments, theintermediate frame comprises between about 1-20 or 3-10 channels in eachof the one or more arrays. In some embodiments of the foregoing aspectand embodiments, the intermediate frame comprises between about 1-35 or3-35 of the arrays of channels on each of the upper and/or lower edgesof the intermediate frame. In some embodiments of the foregoing aspectand embodiments, each of the channels has a depth of between about0.25-10 mm or 0.25-4 mm. In some embodiments of the foregoing aspect andembodiments, each of the channels is in a shape of a circle,semi-circle, rectangular, triangular, or trapezoidal.

In some embodiments of the foregoing aspect and embodiments, the methodfurther comprises contacting the electrolyte with distribution pocketslocated at an end of each of the one or more arrays of channels beforecontacting the electrolyte with the one or more arrays of channels.

In some embodiments of the foregoing aspect and embodiments, the methodfurther comprises contacting the electrolyte with a manifold located atan end of the upper and/or the lower edges of the intermediate framebefore contacting the electrolyte with the distribution pockets.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention may be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1 illustrates some embodiments related to the electrochemical cellcontaining the intermediate frame.

FIGS. 2A and 2B are an illustration of some embodiments related to theintermediate frame.

FIG. 3 illustrates some embodiments related to the intermediate frame.

FIG. 4 illustrates some embodiments related to the array of channelsdrilled in the intermediate frame.

FIG. 5 illustrates some embodiments related to the array of channelswith semi-circular shape in the intermediate frame.

FIG. 6 illustrates some embodiments related to the array of channelswith circular shape in the intermediate frame.

FIG. 7 illustrates some embodiments related to the array of channelswith rectangular shape in the intermediate frame.

FIG. 8 illustrates some embodiments related to the distribution pocketsand the array of channels in the intermediate frame.

FIG. 9 illustrates some embodiments related to the intermediate frame asdescribed in Example 1 herein.

DETAILED DESCRIPTION

Disclosed herein is an intermediate frame, electrochemical systemscomprising the intermediate frame, and methods of using and making thesame.

Before the present invention is described in greater detail, it is to beunderstood that this invention is not limited to particular embodimentsdescribed, as such may, of course, vary. It is also to be understoodthat the terminology used herein is for the purpose of describingparticular embodiments only, and is not intended to be limiting, sincethe scope of the present invention will be limited only by the appendedclaims.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimit of that range and any other stated or intervening value in thatstated range, is encompassed within the invention. The upper and lowerlimits of these smaller ranges may independently be included in thesmaller ranges and are also encompassed within the invention, subject toany specifically excluded limit in the stated range. Where the statedrange includes one or both of the limits, ranges excluding either orboth of those included limits are also included in the invention.

Certain ranges that are presented herein with numerical values may beconstrued as “about” numericals. The “about” is to provide literalsupport for the exact number that it precedes, as well as a number thatis near to or approximately the number that the term precedes. Indetermining whether a number is near to or approximately a specificallyrecited number, the near or approximating unrequited number may be anumber, which, in the context in which it is presented, provides thesubstantial equivalent of the specifically recited number.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present invention, representativeillustrative methods and materials are now described.

All publications and patents cited in this specification are hereinincorporated by reference as if each individual publication or patentwere specifically and individually indicated to be incorporated byreference and are incorporated herein by reference to disclose anddescribe the methods and/or materials in connection with which thepublications are cited. The citation of any publication is for itsdisclosure prior to the filing date and should not be construed as anadmission that the present invention is not entitled to antedate suchpublication by virtue of prior invention. Further, the dates ofpublication provided may be different from the actual publication dateswhich may need to be independently confirmed.

It is noted that, as used herein and in the appended claims, thesingular forms “a,” “an,” and “the” include plural references unless thecontext clearly dictates otherwise. It is further noted that the claimsmay be drafted to exclude any optional element. As such, this statementis intended to serve as antecedent basis for use of such exclusiveterminology as “solely,” “only” and the like in connection with therecitation of claim elements, or use of a “negative” limitation.

As will be apparent to those of skill in the art upon reading thisdisclosure, each of the individual embodiments described and illustratedherein has discrete components and features which may be readilyseparated from or combined with the features of any of the other severalembodiments without departing from the scope or spirit of the presentinvention. Any recited method can be carried out in the order of eventsrecited or in any other order which is logically possible.

Intermediate Frame, Electrochemical Systems, and Methods

In an electrochemical system, there is an anode chamber that houses ananode and an anode electrolyte. There is a cathode chamber that houses acathode and a cathode electrolyte and the anode chamber and the cathodechamber are separated by an ion exchange membrane (IEM). The IEM may bean anion exchange membrane (AEM), a cation exchange membrane (CEM), orboth depending on the desired reactions at the anode and the cathode. Inbetween these components, various additional separator components may beprovided to separate, e.g. the AEM from the anode, the CEM from thecathode and/or AEM from the CEM as well as provide mechanical integrityto the membranes. In addition to these components, individual gaskets orgasket tape may be provided in between and along the outer perimeter ofthe components to seal the compartments from fluid leakage.

In some electrolyzers, the electrochemical system includes the anode andthe cathode separated by both the AEM and the CEM creating a thirdchamber in the middle containing the electrolyte. Provided herein is aunique intermediate frame that separates the AEM from the CEM andcreates the intermediate chamber in the cell. The intermediate framedescribed herein provides amongst other advantages, a spatially uniformelectrolyte flow between the two membranes; provides means to collectelectrolyte flow uniformly across the cell width from opposite end ofthe cell; and provides a substrate to which a spacer can be attached.

In an illustrative embodiment, an electrochemical cell with anintermediate frame is shown in FIG. 1. As illustrated, the cell housesan anode electrode assembly in the anode chamber and a cathode electrodeassembly in the cathode chamber. The two chambers are separated by theAEM and the CEM. Between the AEM and the CEM is the intermediate frameof the invention. Gaskets may be present around the cell's active areain order to form liquid seals. Separators, woven or unwoven, may bepresent to prevent the membranes from touching each other. Many suchcombinations are possible and are within the scope of the invention.

In one aspect, there is provided an intermediate frame in anelectrochemical cell, comprising one or more arrays of channels on upperand/or lower edges of the intermediate frame wherein the channels areconfigured to provide a spatially uniform flow of electrolyte throughthe plane of the intermediate frame. An illustrative embodiment of aportion of the intermediate frame is provided in FIGS. 2A and 2B. Asillustrated in a cross-sectional view of a portion of the intermediateframe in FIG. 2A, the intermediate frame 10 comprises one or more arrays11 of channels 12. These channels may be present on the upper, lower orboth the edges of the intermediate frame. FIG. 3 illustrates theintermediate frame 10 where FIG. 2A illustrates an enlarged view of theportion of the intermediate frame shown in dashed circle. As can be seenin FIG. 3, both the upper as well as the lower edges of the framecontain arrays of the channels. However, the scope of the invention isnot limited to the embodiments illustrated in the figures. Theintermediate frame may have the arrays of the channels on just the upperedge or just the lower edge of the frame. All of those configurationsare well within the scope of the invention. The flow of the electrolytethrough the frame may be from bottom to top or top to bottom. Theintermediate frame provided herein provides spatially uniform flow ofthe electrolyte across the length and/or width of the frame.

Applicants found that in some embodiments, the number of the channels ineach of the arrays and/or the number of arrays of the channels in theupper and/or lower edges of the frame may be critical to the spatiallyuniform flow of the electrolyte through the plane of the intermediateframe. There may be about 1-35 arrays or higher of channels on each ofthe upper edge and/or the lower edge of the intermediate frame. In someembodiments, there may be between about 1-35; or between about 1-30; orbetween about 1-25; or between about 1-20; or between about 1-15; orbetween about 1-10; or between about 1-5; or between about 1-2; orbetween about 3-35; or between about 3-30; or between about 3-25; orbetween about 3-20; or between about 3-15; or between about 3-10; orbetween about 3-5; or between about 5-35; or between about 5-30; orbetween about 5-25; or between about 5-20; or between about 5-15; orbetween about 5-10; or between about 10-35; or between about 10-30; orbetween about 10-25; or between about 10-20; or between about 10-15; orbetween about 15-35; or between about 15-25; or between about 15-20; orbetween about 20-35 or 20-25 arrays of channels on each of the upperedge and/or the lower edge of the intermediate frame. For example, FIG.2B illustrates 5 arrays of channels (described in detail below). In someembodiments, these arrays are equidistant from each other. In someembodiments, each of the arrays or each pocket and the array of channelsin it, is fit between adjacent bolt holes (bolts may be used forsealing). The equidistant arrays may provide a uniform electrolyte flowwhen the electrolyte is fed across the width of the cell.

Each of the one or more arrays may contain between about 1-20 channelsor higher. These channels function as feed channels when the electrolyteis fed through the channels into the intermediate chamber of the cell(intermediate chamber created by the intermediate frame). These channelsmay also function as collection channels when the electrolyte exits theintermediate chamber of the cell. For example, when the electrolyte isfed from the bottom of the cell, the channels at the lower edge of theframe act as feed channels so that the electrolyte flows from the feedchannels through the intermediate chamber and exits from the channelspresent on the upper edge of the frame acting as collection channels.Similarly, when the electrolyte is fed from the top of the cell, thechannels at the upper edge of the frame act as feed channels so that theelectrolyte flows from the feed channels through the intermediatechamber and exits from the channels present on the lower edge of theframe acting as collection channels. In some embodiments, each of theone or more arrays comprise between about 1-20 channels; or betweenabout 2-20 channels; or between about 3-20 channels; or between 5-20channels; or between about 6-20 channels; or between about 8-20channels; or between about 10-20; or between about 12-20; or betweenabout 15-20; or between about 1-15 channels; or between about 3-15channels; or between 5-15 channels; or between about 6-15 channels; orbetween about 8-15 channels; or between about 10-15; or between about1-10 channels; or between about 2-10 channels; or between about 3-10channels; or between 5-10 channels; or between about 6-10 channels; orbetween about 8-10 channels; or between about 3-8 channels; or betweenabout 4-8 channels; or between about 5-8 channels; or between about 1-5channels.

In some embodiments, the channels may be machined into or drilledthrough the frame. For example, the channels can be machined into thepocket that has been machined into the frame, and then the channels andthe pocket are capped. In some embodiments, the channels can be drilledthrough the top and bottom edges of the frame, respectively. Inembodiments where the channels are drilled; the pockets, the caps, andthe shims may not be required. For example, FIG. 4 illustrates an arrayof drilled through channels where the pocket, the cap, and the shim isnot required.

In some embodiments, the channels are configured in such a way that thechannels have a circular, semi-circular, rectangular, triangular,trapezoidal shape or any other similar shape. For example only, in someembodiments, the channels with cap and/or shim (described herein below)have aforementioned shape where the bottom of the channel is thatspecific shape (to maximize structural integrity/resistance to internalpressure and/or facilitate spatially uniform flow of the electrolyte)and the top of the channels is flat owing to the presence of the capand/or the shim. Such embodiment is illustrated in FIG. 5. Across-sectional view of the array of channels is illustrated in FIG. 5,where the channels have a semi-circular shape. Such channels withsemi-circle shape correspond to the intermediate frame illustrated inFIGS. 2A, 2B, and 3.

In some embodiments, the channels have a circular shape. Such channelsmay not have a cap and/or shim requirement since the channels may notcollapse or flow in (as described herein below). FIG. 6 illustrates across-sectional view of the channels of some embodiments where thechannels have a circular shape. The figure A in FIG. 6 illustrates anembodiment where channels are machined on two sheets. One sheet is cutthrough for distribution pocket that is connected to the manifold(explained below), and the other sheet may or may not have thedistribution pocket. The top sheet may be inverted on the bottom sheetand the channels may be lined up as illustrated in B. The two sheets maybe bonded with each other (glue, weld, and the like) or compressedtogether with gasket to form intermediate frame assembly C. FIG. 6illustrates an example of the intermediate frame with channels incircular shape, however, various other means may be employed toconfigure such frame including, but not limited to, machining thechannels by drilling through the frame. All of such methods to configurethe intermediate frame of FIG. 6 are within the scope of the invention.

In some embodiments, the channels have a rectangular shape. In someembodiments, the rectangular shape may have soft edges to maximizestructural integrity/resistance to internal pressure and/or facilitatespatially uniform flow of the electrolyte. FIG. 7 illustrates across-sectional view of the channels where the channels have arectangular shape. Figure A in FIG. 7 illustrates rectangular shapedchannels where the edges of the rectangular shape are softened. Alsoshown in figure B of FIG. 7 is a sideways cross sectional view of therectangular shaped channels where the corners of the channels aresoftened to prevent stress on the adjoining ion exchange membranes(owing to the sharp ends of the channels).

Applicants also found that in some embodiments, the dimensions of thechannel e.g. depth and/or length of the channel may be critical to thespatially uniform flow of the electrolyte through the plane of theintermediate frame. For example, the depth of the channel with thesemi-circular shape is illustrated in FIG. 5. The depth of the channelwith the circular shape is illustrated in FIG. 6. The depth of thechannel with the rectangular shape is illustrated in FIG. 7. The depthof the channels can be configured for any shape of the channels. Thedepth and/or length of the channels may be configured in such a way thatthe channels do not present a large resistance to the flow of theelectrolyte coming into the cell. In some embodiments, the depth of thechannel may be configured in such a way that the dynamic pressure in thecell due to the flow of the electrolyte may remain below roughly 2 psi,or below 1 psi. In some embodiments, the number of channels in eacharray and the depth and/or length of the channels facilitates spatiallyuniform flow of the electrolyte through the plane of the intermediateframe. It is desirable that the thickness of the electrolyte staysuniform across the active area of the cell. Relatively deep pockets ofthe electrolyte may constitute high-resistance current pathways whilerelatively shallow pockets of the electrolyte may constitutelow-resistance current pathways. Furthermore, gas in the cell may needto pass unrestrained along the electrolyte flow path. Stagnant gaspockets may constitute high resistance areas, driving the system awayfrom a uniform current density. Therefore, the spatially uniform flow ofthe electrolyte contributes significantly towards the uniform currentdensity in the cell which is paramount for both performance andreliability of the cell.

In some embodiments, the depth of the channels is between about 0.25-10mm; or between about 0.25-8 mm; or between about 0.25-7 mm; or betweenabout 0.25-6 mm; or between about 0.25-5 mm; or between about 0.25-4 mm;or between about 0.25-3 mm; or between about 0.25-2 mm; or between about0.25-1 mm; or between about 0.25-0.5 mm; or between about 0.5-10 mm; orbetween about 0.5-8 mm; or between about 0.5-6 mm; or between about0.5-5 mm; or between about 0.5-4 mm; or between about 0.5-3 mm; orbetween about 0.5-2 mm; or between about 0.5-1 mm; or between about 1-10mm; or between about 1-8 mm; or between about 1-6 mm; or between about1-5 mm; or between about 1-4 mm; or between about 1-3 mm; or betweenabout 1-2 mm; or between about 2-10 mm; or between about 2-8 mm; orbetween about 2-6 mm; or between about 2-4 mm; or between about 2-3 mm;or between about 3-10 mm; or between about 3-8 mm; or between about 3-6mm; or between about 3-4 mm; or between about 5-10 mm; or between about5-8 mm; or between about 5-6 mm; or between about 8-10 mm.

In some embodiments, the length of the channels is between about 30-100mm; or between about 30-90 mm; or between about 30-80 mm; or betweenabout 30-60 mm; or between about 30-50 mm; or between about 40-100 mm;or between about 40-90 mm; or between about 40-80 mm; or between about40-60 mm; or between about 50-100 mm; or between about 50-90 mm; orbetween about 50-80 mm; or between about 50-70 mm; or between about50-60 mm; or between about 60-100 mm; or between about 60-90 mm; orbetween about 60-80 mm; or between about 60-70 mm; or between about70-100 mm; or between about 80-100 mm; or between about 90-100 mm. Anaspect ratio of the depth of the channel to the length of the channelmay depend on several factors, including but not limited to, electrolyteflow rate, viscosity, gas content etc.

In some embodiments, the intermediate frame further comprisesdistribution pockets located at an end of each of the one or more arraysof channels, configured to distribute the electrolyte to the one or morearrays of channels. FIG. 2A (also FIG. 5) illustrates some embodimentsof the distribution pocket 13 at the end of the array 11 of channels 12,which is configured to distribute the electrolyte to the array ofchannels. The array of channels may be machined into the distributionpockets to distribute the electrolyte into the intermediate chamber ofthe cell. While FIG. 2A illustrates the distribution pocket to be a slotlike design (oval shaped), other designs are equally applicable so longas the channels can be routed along the perimeter of the pockets suchthat the channels are in fluid communication with the distributionpocket which is in fluid communication with the manifold. For exampleonly, another design of the distribution pockets is illustrated in FIG.8 as a top down view of the intermediate frame. For example, thedistribution pocket 13 can be in a shape of a hole (illustrated on theright in FIG. 8) or in a shape of an oval (illustrated on the left inFIG. 8) and the array 11 of channels 12 can be routed along theperimeter of the pocket such that each channel is fed the electrolyte.In embodiments where the distribution pocket is in the shape of a hole(as illustrated in FIG. 8), the channels may be machined such that theyfan out from the center of the hole until they have spread outsufficiently to traverse in parallel fashion to the edge of the frame.Other shapes of the distribution pocket includes, but not limited to,rectangular shape, square shape, triangular shape etc.

The width of the distribution pockets can be as wide as desired. Forexample, in some embodiments, the width of the distribution pockets isbetween about 6-70 mm wide; or between about 6-60 mm wide; or betweenabout 6-50 mm wide; or between about 6-40 mm wide; or between about 6-30mm wide; or between about 6-20 mm wide; or between about 6-10 mm wide;or between about 10-70 mm wide; or between about 10-60 mm wide; orbetween about 10-50 mm wide; or between about 10-40 mm wide; or betweenabout 10-30 mm wide; or between about 10-20 mm wide; or between about20-70 mm wide; or between about 20-60 mm wide; or between about 20-50 mmwide; or between about 20-40 mm wide; or between about 20-30 mm wide; orbetween about 30-70 mm wide; or between about 30-60 mm wide; or betweenabout 30-50 mm wide; or between about 30-40 mm wide; or between about40-70 mm wide; or between about 40-60 mm wide; or between about 40-50 mmwide; or between about 50-70 mm wide; or between about 50-60 mm wide; orbetween about 60-70 mm wide.

In some embodiments, the distribution pockets are operably connected tomanifolds which are located at the end of the upper and/or the loweredges of the intermediate frame, and configured to provide theelectrolyte to and from the distribution pockets. FIG. 2A illustratesprotruding manifold 14. The manifold is located outside the sealedvolume of the intermediate frame and the electrochemical cell. Thechannels enable the electrolyte to flow from (to) an exterior manifoldinto (out of) the cell, across the sealed region.

In some embodiments, the intermediate frame further comprises a cap overeach of the one or more arrays of channels and the correspondingdistribution pocket, configured to prevent the electrolyte from leaking.FIGS. 2A and 2B illustrate caps 15 over the arrays of the channels. FIG.5 also illustrates channels with semi-circle shape having a cap overthem. In some embodiments, the cap can be glued or welded onto the arrayof channels. The caps are glued or welded such that they form aleak-tight assembly. It is desirable to eliminate gaps between the edgeof the caps and the edge of the pockets since the gaps may lead to leakunder the gasket.

In some embodiments, the caps may flow (creep) into the underlyingchannels, thereby choking flow through the channels and/or introducingleakage pathways between the caps and the adjacent gasket. The “flowing”or the “creeping” of the caps, as used herein includes sagging of thecaps into the channels to obstruct the flow of the electrolyte. Thecreeping of the channels by the caps may be prevented by using shims. Insome embodiments, the intermediate frame further comprises a shim underthe cap and over each of the one or more arrays of channels and thecorresponding distribution pocket, configured to prevent the cap fromflowing or creeping into the channels. FIG. 2B illustrates shim 16covering the array 11 of channels 12. The cap 15 goes over the shim 16.In some embodiments, the shim may be made of material that is chemicallycompatible with the electrolyte being flowed and shows sufficientresistance to creep flow at elevated temperature so that it does notflow into the distribution pockets. In some embodiments, the shims aremade of corrosion resistant metal e.g. titanium. The titanium ischemically resistant and is available in thin sheets. The Ti shims mayprovide sufficient rigidity that the caps are prevented from flowinginto the channels. In some embodiments, the shim may be made of anysuitable material, examples include, without limitation, titanium,titanium alloys, stainless steel alloys, nickel, nickel alloys,aluminum, aluminum alloys, copper, copper alloys, hastelloy alloys,inconel alloys, glass-filled chlorinated polyvinyl chloride (CPVC),Rulon®, thermoplastic material such as polyetheretherketone (PEEK),glass-filled polytetrafluoroethylene (PTFE), polypropylene (PP),glass-filled polypropylene (PP), fiberglass reinforced plastic (FRP),polycarbonate, and combinations thereof.

In some embodiments, the thickness of the shim is such that the shimsheet is thin yet is stiff at elevated temperatures. In someembodiments, the shim has a thickness of between about 0.1-1 mm; orbetween about 0.1-0.8 mm; or between about 0.1-0.5 mm; or between about0.1-0.3 mm; or between about 0.25-1 mm; or between about 0.25-0.8 mm; orbetween about 0.25-0.5 mm; or between about 0.25-0.3 mm; or betweenabout 0.3-1 mm; or between about 0.3-0.8 mm; or between about 0.3-0.5mm; or between about 0.5-1 mm; or between about 0.5-0.8 mm; or betweenabout 0.7-1 mm; or between about 0.8-1 mm.

In some embodiments, the internal pressure within the manifold can causethe cap to bulge up in the vicinity of the feed-through holes/slots inthe frame. This bulging of the caps can be prevented by gluing orwelding a thin reinforcement bar over a portion of the caps that extendoutside of the cell sealing area. FIG. 2B illustrates the reinforcementbar 17 over a portion of the cap configured to prevent the cap frombulging out.

The intermediate frame can be either a single piece, or a glued/weldedassembly formed from individual pieces. For example, in someembodiments, the manifolds, shims, caps, and reinforcement bars are allseparate pieces that are attached to the frame to form a leak-tight,sealable assembly. FIG. 3 illustrates the intermediate frame 10 withoutthe reinforcement bar.

In some embodiments, the thickness of the intermediate frame is criticalto maintaining a spatially uniform flow of the electrolyte in theintermediate chamber and is subject to several constraints. Theintermediate frame that separates the AEM from the CEM may need to keepthe membrane separation minimal. The thickness of the intermediate framemay dictate the separation distance between the membranes which in turnmay affect the current resistance. During operation, current passesthrough the electrolyte and the thickness of the electrolyte which isdependent on the thickness of the intermediate frame, may affect theelectrical resistance of the electrolyte. For example, at 300 mA/cm² theelectrical resistance of a typical electrolyte solution may result in avoltage drop of approximately 65 mV per mm of the electrolyte.Therefore, the thicker is the frame, the thicker is the electrolyte flowand higher may be the voltage drop.

Further, the thickness of the electrolyte needs to be uniform across theactive area of the cell in order to maintain uniform current density.Relatively deep pockets of the electrolyte may constitutehigh-resistance current pathways; relatively shallow pockets of theelectrolyte constitute low-resistance current pathways. The thickness ofthe electrolyte may be controlled by using an appropriate thickness ofthe intermediate frame and the arrays of the channels therein.

Furthermore, the thickness of the intermediate frame may need to preventor minimize sharp bends of either the AEM or CEM. Bending of themembranes may result in internal stress that can reduce membranelifetime. Additionally, the membranes may not contact one-another whenseparated by the intermediate frame. The contacting of the membranes mayresult in a short that can damage or destroy the cell. Therefore, thethickness of the intermediate frame provided herein needs to be suchthat optimum separation of the membranes is achieved; optimum thicknessof the electrolyte flows through the intermediate chamber; uniformthickness of the electrolyte flows through the frame; and the frame caneasily accommodate the channel design.

In some embodiments, the thickness of such intermediate frame is betweenabout 0.75-30 mm; or between about 0.75-25 mm; or between about 0.75-20mm; or between about 0.75-15 mm; or between about 0.75-10 mm; or betweenabout 0.75-5 mm; or between about 0.75-2 mm; or between about 1-30 mm;or between about 1-25 mm; or between about 1-20 mm; or between about1-15 mm; or between about 1-10 mm; or between about 1-6 mm; or betweenabout 1-5 mm; or between about 1-3 mm; or between about 2-30 mm; orbetween about 2-25 mm; or between about 2-20 mm; or between about 2-15mm; or between about 2-10 mm; or between about 2-6 mm; or between about2-5 mm; or between about 2-3 mm; or between about 3-30 mm; or betweenabout 3-20 mm; or between about 3-10 mm; or between about 3-6 mm; orbetween about 3-5 mm; or between about 4-30 mm; or between about 4-20mm; or between about 4-10 mm; or between about 4-6 mm; or between about5-30 mm; or between about 5-20 mm; or between about 5-10 mm; or betweenabout 5-6 mm; or between about 10-30 mm; or between about 10-20 mm; orbetween about 20-30 mm. In some embodiments, the intermediate frame ofthickness between about 0.75-30 mm comprises about 1-20 channels in eacharray where the intermediate frame has between about 1-35 arrays ofchannels. In some embodiments, the intermediate frame of thicknessbetween about 1-6 mm comprises about 3-10 channels in each array wherethe intermediate frame has between about 3-35 arrays of channels. Insome embodiments, the foregoing intermediate frame comprises channelshaving a depth of between about 0.25-10 mm; or between about 0.25-8 mm;or between about 0.25-5 mm; or between about 0.25-4 mm.

In some embodiments, the intermediate frame is made of material that isresistant to acidic and/or basic mediums, variable temperature ranges,and metal ion containing anolytes. For example, the intermediate framemay be made of titanium or a polymeric material. Examples of polymericmaterials include, without limitation, chlorinated polyvinyl chloride(CPVC), heat stabilized polypropylene (PP), ULTEM, PEEK, glass-filledPTFE, PTFE, glass-filled PP, glass-filled CPVC, styrene copolymer, fiberglass reinforced plastic (FRP), or combinations thereof. In someembodiments, the intermediate frame is configured to withstandtemperature between about 70-150° C. In some embodiments, theintermediate frame is configured to withstand pressure between 2-10 psi.

In some embodiments, the intermediate frame further comprises a spacerin an open area in middle of the intermediate frame. The open area isillustrated as 17 in the intermediate frame 10 of FIG. 3. The open spacein the frame may have a spacer material in order to further prevent themembranes from contacting each other. The spacer may be held in place inthe intermediate frame by any means. Example include without limitation,hooks or pegs in the frame to hold the spacer in place. The spacer maybe made of any polymeric materials listed herein. In some embodiments,the thickness of the spacer may be less than or equal to theintermediate frame. In some embodiments, the spacer may present littleresistance to the electrolyte flow, readily release gas, and providesufficient coverage to prevent membranes from contacting each other. Insome embodiments, the spacer may be configured to withstand temperaturebetween about 70-150° C. and/or pressure between 2-10 psi.

In some embodiments there is provided an intermediate frame in anelectrochemical cell, comprising one or more arrays of channels on upperand/or lower edges of the intermediate frame wherein the channels areconfigured to provide a spatially uniform flow of electrolyte throughthe plane of the intermediate frame wherein the intermediate framecomprises between about 1-20 channels in each of the arrays, wherein theintermediate frame comprises between about 1-35 arrays of channels oneach of the upper and/or lower edges of the intermediate frame, andwherein the depth of each of the channel is between about 0.25-10 mm. Insome embodiments, the foregoing intermediate frame is of thicknessbetween about 0.75-30 mm.

In some embodiments there is provided an intermediate frame in anelectrochemical cell, comprising one or more arrays of channels on upperand/or lower edges of the intermediate frame wherein the channels areconfigured to provide a spatially uniform flow of electrolyte throughthe plane of the intermediate frame wherein the intermediate framecomprises between about 3-7 channels in each of the arrays, wherein theintermediate frame comprises between about 5-25 arrays of channels oneach of the upper and/or lower edges of the intermediate frame, andwherein the depth of each of the channel is between about 0.25-4 mm. Insome embodiments, the foregoing intermediate frame is of thicknessbetween about 1-6 mm.

One or more of the foregoing aspects and embodiments related to thechannels, arrays of the channels, distribution pockets, manifolds, caps,shims, spacer, and/or reinforcement bars may be combined to provide theintermediate frame of the invention.

In another aspect, there is provided an electrochemical system thatcontains the intermediate frame provided herein.

In one aspect, there is provided an electrochemical system comprising ananode chamber comprising an anode in contact with an anode electrolyte;a cathode chamber comprising a cathode in contact with a cathodeelectrolyte; and an intermediate frame comprising one or more arrays ofchannels on upper and/or lower edges of the intermediate frame whereinthe channels are configured to provide a spatially uniform flow ofelectrolyte through the plane of the intermediate frame. Variousembodiments related to the material of construction of the intermediateframe and the configuration of the channels, arrays of the channels,distribution pockets, manifolds, caps, shims, spacer, and/orreinforcement bars, have been described herein and all of thoseconfigurations are applicable to the foregoing electrochemical systems.

In the foregoing aspects, in some embodiments, the anode is configuredto oxidize the metal ions from a lower oxidation state to a higheroxidation state. For example, in some embodiments, the anode isconfigured to oxidize copper ions from Cu(I)Cl to Cu(II)Cl₂. Examples ofthe other metal ions include, without limitation, copper ions, platinumions, tin ions, chromium ions, iron ions etc. The metal ions may bepresent as a metal halide or a metal sulfate.

The electrochemical cell provided herein may be any electrochemical cellthat uses an intermediate frame. The reactions in the electrochemicalcell using the components of the invention may be any reaction carriedout in the electrochemical cell including but not limited tochlor-alkali processes. In some embodiments, the electrochemical cellhas an anode electrolyte containing metal ions and the anode oxidizesthe metal ions from the lower oxidation state to the higher oxidationstate in the anode chamber. Such electrochemical cells have beendescribed in detail in U.S. Pat. No. 9,187,834, issued Nov. 17, 2015,which is incorporated herein by reference in its entirety.

In the electrochemical cells provided herein, the cathode reaction maybe any reaction that does or does not form an alkali in the cathodechamber. Such cathode consumes electrons and carries out any reactionincluding, but not limited to, the reaction of water to form hydroxideions and hydrogen gas; or reaction of oxygen gas and water to formhydroxide ions; or reduction of protons from an acid such ashydrochloric acid to form hydrogen gas; or reaction of protons fromhydrochloric acid and oxygen gas to form water. In some embodiments, theelectrochemical cells may include production of alkali in the cathodechamber of the cell.

The electron(s) generated at the anode are used to drive the reaction atthe cathode. The cathode reaction may be any reaction known in the art.The anode chamber and the cathode chamber are separated by the IEMs andthe intermediate frame provided herein that may allow the passage ofions, such as, but not limited to, sodium ions in some embodiments tothe cathode electrolyte if the electrolyte in the intermediate chamberis sodium chloride, sodium bromide, sodium iodide, sodium sulfate; orammonium ions if the electrolyte is ammonium chloride etc.; or anequivalent solution containing metal halide. In some embodiments, theIEMs and the intermediate frame allows the passage of anions, such as,but not limited to, chloride ions, bromide ions, iodide ions, or sulfateions to the anode electrolyte if the electrolyte in the intermediatechamber is e.g., sodium chloride, sodium bromide, sodium iodide, orsodium sulfate or an equivalent solution. The sodium ions may combinewith hydroxide ions in the cathode electrolyte to form sodium hydroxide.The anions may combine with metal ions in the anode electrolyte to formmetal halide or metal sulfate.

In some embodiments of the electrochemical cell, the electrolyte (e.g.,sodium chloride, sodium bromide, sodium iodide, sodium sulfate, ammoniumchloride, HCl, or combinations thereof or an equivalent solution) isdisposed through the manifold into the intermediate frame between theAEM and the CEM. The ions, e.g. sodium ions, from the electrolyte passfrom the intermediate chamber through CEM to form e.g. sodium hydroxidein the cathode chamber and the halide anions such as, chloride, bromideor iodide ions, or sulfate anions, from the electrolyte pass from theintermediate chamber through the AEM to form HCl or a solution for metalhalide or metal sulfate in the anode chamber. The electrolyte, after thetransfer of the ions, can be withdrawn from the intermediate frame inthe intermediate chamber (through the distribution pockets and manifoldsin the lower edge of the frame if the flow of the electrolyte is fromtop to bottom) as depleted ion solution. For example, in someembodiments when the electrolyte is sodium chloride solution, then afterthe transfer of the sodium ions to the cathode electrolyte and transferof chloride ions to the anode electrolyte, the depleted sodium chloridesolution may be withdrawn from the intermediate frame in theintermediate chamber.

The electrochemical cells in the methods and systems provided herein aremembrane electrolyzers. The electrochemical cell may be a single cell ormay be a stack of cells connected in series or in parallel. Theelectrochemical cell may be a stack of 5 or 6 or 50 or 100 or moreelectrolyzers connected in series or in parallel. Each cell comprisesthe anode, the cathode, the AEM, the CEM, and the intermediate frame, asillustrated in FIG. 1. In some embodiments, the electrolyzers providedherein are monopolar electrolyzers. In the monopolar electrolyzers, theelectrodes may be connected in parallel where all anodes and allcathodes are connected in parallel. In such monopolar electrolyzers, theoperation takes place at high amperage and low voltage. In someembodiments, the electrolyzers provided herein are bipolarelectrolyzers. In the bipolar electrolyzers, the electrodes may beconnected in series where all anodes and all cathodes are connected inseries. In such bipolar electrolyzers, the operation takes place at lowamperage and high voltage. In some embodiments, the electrolyzers are acombination of monopolar and bipolar electrolyzers and may be calledhybrid electrolyzers.

In some embodiments of the bipolar electrolyzers as described above, thecells are stacked serially constituting the overall electrolyzer and areelectrically connected in two ways. In bipolar electrolyzers, a singleplate, called bipolar plate, may serve as base plate for both thecathode and anode. The electrolyte solution may be hydraulicallyconnected through common manifolds and collectors internal to the cellstack. The stack may be compressed externally to seal all frames andplates against each other, which are typically referred to as a filterpress design. In some embodiments, the bipolar electrolyzer may also bedesigned as a series of cells, individually sealed, and electricallyconnected through back-to-back contact, typically known as a singleelement design. The single element design may also be connected inparallel in which case it would be a monopolar electrolyzer.

In some embodiments, the anode used in the electrochemical systems maycontain a corrosion stable base support. Other examples of basematerials include, but not limited to, sub-stoichiometric titaniumoxides, such as, Magneli phase sub-stoichiometric titanium oxides havingthe formula TiO_(x) wherein x ranges from about 1.67 to about 1.9. Someexamples of titanium sub-oxides include, without limitation, titaniumoxide Ti₄O₇. The base materials also include, without limitation, metaltitanates such as M_(x)Ti_(y)O_(z) such as M_(x)Ti₄O₇, etc.

In some embodiments, the anode is not coated with an electrocatalyst. Insome embodiments, the electrodes described herein (including anodeand/or cathode) contain an electrocatalyst for aiding in electrochemicaldissociation, e.g. reduction of oxygen at the cathode or the oxidationof the metal ion at the anode. Examples of electrocatalysts include, butnot limited to, highly dispersed metals or alloys of the platinum groupmetals, such as platinum, palladium, ruthenium, rhodium, iridium, ortheir combinations such as platinum-rhodium, platinum-ruthenium,titanium mesh coated with PtIr mixed metal oxide or titanium coated withgalvanized platinum; electrocatalytic metal oxides, such as, but notlimited to, IrO₂; silver, gold, tantalum, carbon, graphite,organometallic macrocyclic compounds, and other electrocatalysts wellknown in the art for electrochemical reduction of oxygen or oxidation ofmetal.

In some embodiments, the electrodes described herein, relate to poroushomogeneous composite structures as well as heterogeneous, layered typecomposite structures wherein each layer may have a distinct physical andcompositional make-up, e.g. porosity and electroconductive base toprevent flooding, and loss of the three phase interface, and resultingelectrode performance.

Any of the cathodes provided herein can be used in combination with anyof the anodes described above. In some embodiments, the cathode used inthe electrochemical systems of the invention, is a hydrogen gasproducing cathode. In some embodiments, the cathode used in theelectrochemical systems of the invention, is a hydrogen gas producingcathode that does not form an alkali. The hydrogen gas may be vented outor captured and stored for commercial purposes. In some embodiments, thecathode in the electrochemical systems of the invention may be agas-diffusion cathode. In some embodiments, the gas-diffusion cathode,as used herein, is an oxygen depolarized cathode (ODC). The oxygen atthe cathode may be atmospheric air or any commercial available source ofoxygen. In some embodiments, the cathode in the electrochemical systemsof the invention may be a gas-diffusion cathode that reacts HCl andoxygen gas to form water. The oxygen at the cathode may be atmosphericair or any commercial available source of oxygen.

In some embodiments, the electrolyte in the electrochemical systems andmethods described herein include the aqueous medium containing more than1 wt % water. In some embodiments, the aqueous medium includes more than1 wt % water; more than 5 wt % water; or more than 5.5 wt % water; ormore than 6 wt %; or more than 20 wt % water; or more than 25 wt %water; or more than 30 wt % water. In some embodiments, the aqueousmedium may comprise an organic solvent such as, e.g. water solubleorganic solvent.

In some embodiments of the methods and systems described herein, theamount of total metal ion in the anode electrolyte in theelectrochemical cell or the amount of copper in the anode electrolyte orthe amount of iron in the anode electrolyte or the amount of chromium inthe anode electrolyte or the amount of tin in the anode electrolyte orthe amount of platinum is between 1-12M; or between 1-11M; or between1-10M; or between 1-9M; or between 1-8M; or between 1-7M; or between1-6M; or between 1-5M; or between 1-4M; or between 1-3M; or between1-2M. In some embodiments, the amount of total ion in the anodeelectrolyte, as described above, is the amount of the metal ion in thelower oxidation state plus the amount of the metal ion in the higheroxidation state; or the total amount of the metal ion in the higheroxidation state; or the total amount of the metal ion in the loweroxidation state.

In some embodiments of the methods and systems described herein, theanode electrolyte in the electrochemical systems and methods providedherein contains the metal ion in the higher oxidation state in the rangeof 4-7M, the metal ion in the lower oxidation state in the range of0.1-2M and the electrolyte in the intermediate chamber e.g. sodiumchloride in the range of 1-3M. The anode electrolyte may optionallycontain 0.01-0.1M hydrochloric acid. In some embodiments of the methodsand systems described herein, the anode electrolyte may contain anothercation in addition to the metal ion. Other cation includes, but is notlimited to, alkaline metal ions and/or alkaline earth metal ions, suchas but not limited to, lithium, sodium, calcium, magnesium, etc. Theamount of the other cation added to the anode electrolyte may be between0.01-5M; or between 0.01-1M; or between 0.05-1M; or between 0.5-2M; orbetween 1-5M.

In some embodiments, the aqueous electrolyte including the catholyte orthe cathode electrolyte and/or the anolyte or the anode electrolyte, orthe electrolyte introduced into the intermediate frame disposed betweenthe AEM and the CEM, in the systems and methods provided herein include,but not limited to, saltwater or fresh water. The saltwater includes,but is not limited to, seawater, brine, and/or brackish water. Saltwateris employed in its conventional sense to refer to a number of differenttypes of aqueous fluids other than fresh water, where the saltwaterincludes, but is not limited to, brine as well as other salines having asalinity that is greater than that of freshwater. Brine is watersaturated or nearly saturated with salt and has a salinity that is 50ppt (parts per thousand) or greater.

In some embodiments, the electrolyte including the cathode electrolyteand/or the anode electrolyte and/or the electrolyte introduced into theintermediate frame, such as, saltwater include water containing morethan 1% chloride content, e.g. alkali metal halides including sodiumhalide, potassium halide etc. e.g. more than 1% NaCl; or more than 10%NaCl; or more than 50% NaCl; or more than 70% NaCl; or between 1-99%NaCl; or between 1-70% NaCl; or between 1-50% NaCl; or between 1-10%NaCl; or between 10-99% NaCl; or between 10-50% NaCl; or between 20-99%NaCl; or between 20-50% NaCl; or between 30-99% NaCl; or between 30-50%NaCl; or between 40-99% NaCl; or between 40-50% NaCl; or between 50-90%NaCl; or between 60-99% NaCl; or between 70-99% NaCl; or between 80-99%NaCl; or between 90-99% NaCl; or between 90-95% NaCl. In someembodiments, the above recited percentages apply to ammonium chloride,ferric chloride, sodium bromide, sodium iodide, or sodium sulfate as anelectrolyte. The percentages recited herein include wt % or wt/wt % orwt/v %. It is to be understood that all the electrochemical systemsdescribed herein that contain sodium chloride can be replaced with othersuitable electrolytes, such as, but not limited to, ammonium chloride,sodium bromide, sodium iodide, sodium sulfate, potassium salts, orcombination thereof.

As used herein, the “voltage” includes a voltage or a bias applied to ordrawn from an electrochemical cell that drives a desired reactionbetween the anode and the cathode in the electrochemical cell. In someembodiments, the desired reaction may be the electron transfer betweenthe anode and the cathode such that an alkaline solution, water, orhydrogen gas is formed in the cathode electrolyte and the metal ion isoxidized at the anode. In some embodiments, the desired reaction may bethe electron transfer between the anode and the cathode such that themetal ion in the higher oxidation state is formed in the anodeelectrolyte from the metal ion in the lower oxidation state. The voltagemay be applied to the electrochemical cell by any means for applying thecurrent across the anode and the cathode of the electrochemical cell.Such means are well known in the art and include, without limitation,devices, such as, electrical power source, fuel cell, device powered bysun light, device powered by wind, and combinations thereof. The type ofelectrical power source to provide the current can be any power sourceknown to one skilled in the art. For example, in some embodiments, thevoltage may be applied by connecting the anodes and the cathodes of thecell to an external direct current (DC) power source. The power sourcecan be an alternating current (AC) rectified into DC. The DC powersource may have an adjustable voltage and current to apply a requisiteamount of the voltage to the electrochemical cell.

In some aspects, there are provided methods to use and make theintermediate frame and/or the electrochemical systems containing theintermediate frame provided herein.

In one aspect, there is provided a method of using an intermediate framein an electrochemical cell, comprising:

applying voltage to an anode and a cathode in an electrochemical cell;

contacting the anode with an anode electrolyte in an anode chamber;

contacting the cathode with a cathode electrolyte in a cathode chamber;and

contacting an electrolyte with an intermediate frame wherein theintermediate frame comprises one or more arrays of channels on upperand/or lower edges of the intermediate frame wherein the channels areconfigured to provide a spatially uniform flow of the electrolytethrough the plane of the intermediate frame.

In one aspect, there is provided a method of using an intermediate framein an electrochemical cell, comprising:

applying voltage to an anode and a cathode in an electrochemical cell;

contacting the anode with an anode electrolyte wherein the anodeelectrolyte comprises metal ions and the anode oxidizes the metal ionsfrom a lower oxidation state to a higher oxidation state;

contacting the cathode with a cathode electrolyte in a cathode chamber;and

contacting an electrolyte with an intermediate frame wherein theintermediate frame comprises one or more arrays of channels on upperand/or lower edges of the intermediate frame wherein the channels areconfigured to provide a spatially uniform flow of the electrolytethrough the plane of the intermediate frame.

In some embodiments of the foregoing aspects, the intermediate framewithstands temperature between about 70-150° C. and/or the intermediateframe withstands pressure between 2-10 psi.

In some embodiments of the foregoing aspects and embodiments, thechannels provide a spatially uniform flow of the electrolyte through thewidth of the electrochemical cell.

In some embodiments of the foregoing aspects and embodiments, the methodfurther comprises contacting an anion exchange membrane between theintermediate frame and the anode and contacting a cation exchangemembrane between the intermediate frame and the cathode.

In some embodiments of the foregoing aspects and embodiments, theintermediate frame provides advantages (also described herein above)selected from the group consisting of minimal membrane separation;uniform current density; no bending of the membrane; low dynamicpressure in the cell; minimal resistance to the electrolyte and gas; andcombinations thereof.

In some embodiments of the foregoing aspects and embodiments, theintermediate frame comprises between about 1-20 or 3-10 channels in eachof the one or more arrays. In some embodiments of the foregoing aspectsand embodiments, the intermediate frame comprises between about 1-35 or3-35 of the arrays of channels on each of the upper and/or lower edgesof the intermediate frame. In some embodiments of the foregoing aspectsand embodiments, each of the channels has a depth of between about0.25-10 mm or 0.25-4 mm.

In some embodiments of the foregoing aspects and embodiments, the methodfurther comprises contacting the electrolyte with distribution pocketslocated at an end of each of the one or more arrays of channels beforecontacting the electrolyte with the one or more arrays of channels. Insome embodiments, the distribution pockets are between about 6-70 mmwide.

In some embodiments of the foregoing aspects and embodiments, the methodfurther comprises contacting the electrolyte with a manifold located atan end of the upper and/or the lower edges of the intermediate framebefore contacting the electrolyte with the distribution pockets.

In some embodiments of the foregoing aspects and embodiments, the methodfurther comprises placing a cap over each of the one or more arrays ofchannels and the corresponding distribution pocket to prevent theelectrolyte from leaking.

In some embodiments of the foregoing aspects and embodiments, the methodfurther comprises placing a shim under the cap and over each of the oneor more arrays of channels and the corresponding distribution pocket toprevent the cap from flowing into the channels.

In some embodiments of the foregoing aspects and embodiments, the shimhas a thickness of between about 0.1-1 mm.

In some embodiments of the foregoing aspects and embodiments, the methodfurther comprises placing a reinforcement bar over a portion of the capto prevent the cap from bulging out.

In some embodiments of the foregoing aspects and embodiments, thethickness of the intermediate frame is between about 0.75-30 mm or 1-6mm.

In some embodiments of the foregoing aspects and embodiments, the methodfurther comprises placing a spacer in an open area in middle of theintermediate frame. In some embodiments, the method further comprisesholding the spacer in place using means such as but not limited to,pegs, clips, hooks or the like. In some embodiments, the spacer may bewelded or glued to the intermediate frame.

The following examples are put forth so as to provide those of ordinaryskill in the art with a complete disclosure and description of how tomake and use the present invention, and are not intended to limit thescope of what the inventors regard as their invention nor are theyintended to represent that the experiments below are all or the onlyexperiments performed. Various modifications of the invention inaddition to those described herein will become apparent to those skilledin the art from the foregoing description and accompanying figures. Suchmodifications fall within the scope of the appended claims. Efforts havebeen made to ensure accuracy with respect to numbers used (e.g. amounts,temperature, etc.) but some experimental errors and deviations should beaccounted for. Unless indicated otherwise, parts are parts by weight,molecular weight is weight average molecular weight, temperature is indegrees Centigrade, and pressure is at or near atmospheric.

EXAMPLES Example 1 Electrochemical System with Intermediate Frame

The cell was built up layer by layer starting with the anode. Afteradding the AEM, a gasket was placed around the perimeter of the cell.The intermediate frame, made of CPVC, was then positioned on the gasket.The intermediate frame contained seven channels per array and fivearrays of channels on each upper and lower edges of the frame, where thedepth of each channel was about 0.74 mm. The thickness of the frame wasabout 3.2 mm. The separator was next added to the center region of theintermediate frame. A gasket was then placed along the perimeter of theintermediate frame. The CEM was then added. Another gasket was placed onthe CEM. Finally, the cathode was positioned on top of the whole stack.Flange bars were positioned against the outer flanges of both the anodeand the cathode. Bolts were positioned into all of the holes such thatthey spanned from anode loading bar to cathode loading bar. Nuts wereadded to all bolts. The nuts were tightened in a controlled sequence (toinsure good sealing) to a preliminary torque. The same tighteningsequence was then repeated using the final torque. Thus, all adjacentcomponents between the anode and cathode flanges were sealed usingcompressed gaskets.

Fluid and electrical connections were made. The intermediate chambercreated by the intermediate frame was filled with sodium chlorideelectrolyte solution. While the electrolyte continued to flow, thecathode was filled with caustic solution. Once the cathode was full, theanode was filled with copper solution containing sodium chloride(anolyte). A rectifier was used to drive the desired current through thecell once all three streams were flowing through the cell. Duringoperation, the temperature of all the three streams (and thus the cellcomponents) was approximately 90° C. The electrolyte, caustic solution,and copper solution flow rates were approximately 110 kg/h, 70 kg/h and400 kg/h, respectively, throughout each run.

As illustrated in FIG. 9, the intermediate frame design with array ofchannels, caps, and shims, worked efficiently. The intermediate framehad shims under the caps. The caps did not flow into and clog thechannels and there was no outward bulging of the caps by the internalelectrolyte pressure.

Example 2 Electrochemical System with Intermediate Frame

The cell was built up layer by layer starting with the anode, asdescribed in Example 1 above. The intermediate frame contained fivechannels per array and one array of channels on each upper and loweredges of the frame, where the depth of each channel was about 1 mm. Thethickness of the frame was about 3.2 mm. The intermediate frame was madeof heat stabilized polypropylene. The electrochemical cell was run, asdescribed in Example 1. The electrolyte, caustic solution, and coppersolution flow rates were approximately 7 kg/h, 7 kg/h and 20 kg/h,respectively, throughout each run. This intermediate frame design witharray of channels worked efficiently.

1-22. (canceled)
 23. A method of using an intermediate frame in anelectrochemical cell, comprising: contacting an electrolyte with anintermediate frame wherein the intermediate frame comprises betweenabout 3-35 arrays of channels on upper and/or lower edges of theintermediate frame wherein the channels traverse in parallel fashion andproviding a spatially uniform flow of the electrolyte through plane ofthe intermediate frame; contacting the electrolyte with distributionpockets located on the upper and/or the lower edges of the intermediateframe at an end of each of the arrays of channels and providing theelectrolyte from the distribution pockets to each of the arrays ofchannels and/or from each of the arrays of channels to the distributionpockets; and contacting the electrolyte with an exterior manifoldlocated outside sealed volume of the intermediate frame at an end of theupper and/or the lower edges of the intermediate frame and providing theelectrolyte from the exterior manifold to the distribution pocketsand/or from the distribution pockets to the exterior manifold.
 24. Themethod of claim 23, wherein the intermediate frame provides advantagesselected from the group consisting of minimal membrane separation;uniform current density; no bending of the membrane; low dynamicpressure in the cell; minimal resistance to the electrolyte and gas; andcombinations thereof.
 25. The method of claim 23, comprising betweenabout 2-20 channels in each of the 3-35 arrays of channels.
 26. Themethod of claim 23, comprising between about 5-30 arrays of channels oneach of the upper and/or lower edges of the intermediate frame.
 27. Themethod of claim 23, wherein each of the channels has a depth of betweenabout 0.25-10 mm; has a length of between about 30-100 mm; orcombination thereof.
 28. The method of claim 23, wherein each of thechannels is in a shape of a circle, semi-circle, rectangular,triangular, or trapezoidal.
 29. The method of claim 23, wherein thedistribution pockets are between about 6-70 mm wide.
 30. The method ofclaim 23, wherein thickness of the intermediate frame is between about0.75-30 mm.
 31. The method of claim 23, further comprising providing acap over each of the 3-35 arrays of channels and the correspondingdistribution pocket and preventing the electrolyte from leaking.
 32. Themethod of claim 31, further comprising providing a shim under the capand covering each of the 3-35 arrays of channels and the correspondingdistribution pocket and preventing the cap from flowing into thechannels.
 33. The method of claim 32, wherein the shim has a thicknessof between about 0.1-1 mm.
 34. The method of claim 31, furthercomprising providing a reinforcement bar over a portion of the cap andpreventing the cap from bulging out.
 35. The method of claim 23, furthercomprising contacting an anode with an anode electrolyte in an anodechamber in the electrochemical cell; contacting a cathode with a cathodeelectrolyte in a cathode chamber in the electrochemical cell; andapplying voltage to the anode and the cathode.
 36. The method of claim35, further comprising contacting an anion exchange membrane between theintermediate frame and the anode and contacting a cation exchangemembrane between the intermediate frame and the cathode.
 37. The methodof claim 23, further comprising providing a spacer in an open area inmiddle of the intermediate frame.
 38. The method of claim 23, furthercomprising flowing the electrolyte through the intermediate frame frombottom to top or top to bottom.
 39. The method of claim 23, wherein theelectrolyte is an alkali metal halide solution and/or alkaline earthmetal halide solution.
 40. The method of claim 23, further comprisingcontacting a cathode with a cathode electrolyte in a cathode chamber inthe electrochemical cell and reacting water at the cathode to formhydroxide ions and hydrogen gas; reacting oxygen gas and water at thecathode to form hydroxide ions; reducing protons from hydrochloric acidat the cathode to form hydrogen gas; or reacting protons fromhydrochloric acid and oxygen gas at the cathode to form water.